9990990 has 48 divisors (see below), whose sum is σ = 26822016. Its totient is φ = 2577600.

The previous prime is 9990989. The next prime is 9990997. The reversal of 9990990 is 990999.

9990990 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9990997) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1000 + ... + 4580.

It is an arithmetic number, because the mean of its divisors is an integer number (558792).

Almost surely, 2^9990990 is an apocalyptic number.

9990990 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 9990990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13411008).

9990990 is an abundant number, since it is smaller than the sum of its proper divisors (16831026).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

9990990 is a wasteful number, since it uses less digits than its factorization.

9990990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3625 (or 3622 counting only the distinct ones).

The product of its (nonzero) digits is 59049, while the sum is 45.

The square root of 9990990 is about 3160.8527330453. The cubic root of 9990990 is about 215.3787447052.

It can be divided in two parts, 99909 and 90, that added together give a palindrome (99999).

The spelling of 9990990 in words is "nine million, nine hundred ninety thousand, nine hundred ninety".